Frictional gearing



(No Model.)

fr. HUNDERWOOD. FRIGTIONAL GBARING.

No. 451,987. Patented May 12, 1891.

` Illa UNITED STATES PATENT Fries.

FRANK. H. UNDERVOOD, OF TOLLAND, CONNECTICUT.

FRICTIONAL GEARING.

SPECIFICATION forming' part Of Letters Patent NO. 451,987, dated May 12, 1891.

Application filed January 20, 1891l Serial No. 378,417. (No model.)

To all whom t may concern:

Be it known that I, FRANK. 1I. UNDERWOOD, a citizen of the United States, residing at Tolland, in the county of Tolland and State of Connecticut, have invented certain new and useful Improvements in Frictional Gearing, of Which the following is a specification.

This invention relates to that class of frietional gearing in which one grooved Wheel is driven from another grooved wheel through an intermediate driving-ring freely encircling the driven Wheel.

The object of the invention is to provide improved frictional gearing of the class speciiied, constructed, and organized for superior eiiciency. n

In the drawings accompanying and forniing a part of this specification, Figure 1 is a side elevation of frictional gearing constructed and organized according to my presentinvention. Fig. 2 is a horizontal sectional view in the line a a, Fig. 1. Fig. 3 is a view similar to a portion of Fig. 2 and is illustrative of certain features of the invention. Fig. a is a sectional elevation similar to a portion of Fig. 1, and is in the nature of a diagrammatic view illustrating certain features of the organization of the gearing. Fig. 5 is a diagrammatic view further illustrative of said organization. Fig. 6 is a diagrammatic view showing the outline of a section of the driving-ring in the plane of the thrust-line l) b, Fig. 5.

Similar characters designate like parts in all the iigures.

My improved frictional gearing comprises a driving-wheel and its shaft, a driven Wheel and its shaft, and a driving-ring freely encircling the driven wheel and engaging both Wheels. The driving-shaft is designated by S Aand the driven shaft by N. The driving-Wheel C is suitably affixed to the drivingshaft S and has a groove 7, whose opposing conical faces 6 and S constitute frictional driving-faces. The driven wheel F, which is suitably supported by the driven shaft N or otherwise, has a corresponding groove 9, Whose opposing conical faces let and 16 constitute frictional driving-faces substantially similar to the corresponding faces 6 andS, respectively, of the driving-Wheel. The driving and driven Wheels are,in ordinary practice, made of cast-iron, the driving-faces thereof being truly turned and the Wheels being usually set to run in the same plane.

The driving-ring, designated in a general Way by R, is a substantially circular continuous ring, having, as shown in cross-sectional outline in Figs. 2 and 3, oppositely-disposed pairs of oppositely-disposed frictional driving-faces G and 8 and' 14 and 16', corresponding to the aforesaid driving-faces of the driving and driven Wheels, respectively. The driving-ring is preferably made of leather, and may be constructed "of successive layers or rings superimposed one upon the other, the Whole being securely fastened together and properly shaped.

The driving-ring, as will be observed from Figs. 1 to 5, inclusive, has a considerable thickness measured in its plane of revolution or diametrically of the Wheels, While the angles of the grooves of the driving-Wheels arerelatively acute. From these features it Will be understood that a certain portion of the surface of the driving-ring engages with a certain portion of the surface of the Wheel-faces. By reason of the convexity (or concavity) of the one surface relative to the other there is in each pair of said contacting surfaces a certain point of greater pressure, which point may be properly designated as the center of resistance. In the case of a system of driving-gearing proportioned as shown in the drawings those centers of resistance will be approximately the points 2. and 4, Fig. 5, the line b b extending through said points indicating the direction of the line of thrust from the driving- Wheel to the driven Wheel, respectively. Referring again to Fig. 2 it will be seen that the angle 3 of the driving-faces 6 and S is greater than the angle of repose for the materials used, the wheels being of iron, While the driving-ring is of leather; but the actual angle of repose is to be measured in the plane of the line of thrust and not in a plane radial to the Wheel. When thus measured, said angle of repose is reduced from the angle 3 shown in Fig. 2 to the angle 3 shown in Fig. 6, said angle 3 being Within the normal angle of repose for the specified materials. In like manner the angle 5, Fig. 3, of the driven Wheel IOO is reduced to the angle 5, Fig. t3, when measured in the plane of the line of thrust b l), Fig. 5. The practical result of this peculiar construction and organization of the described parts, the driving-ring being properly engaged between the two wheels, is to lock said ring between the driving and driven wheels with a force proportionate to the thrust of the driving-wheel. This locking of the wheel-engaging portion of the drivingring between the two wheels, as set forth, permits the wheels to be slightly separated, so that the driving-ring does not entirely fill the space between the two wheels in the plane of their centers, which plane is on the line a a, Fig. 5, and corresponds to the plane of the section shown in Fig. 3. The result of this organization is to carry the point 4 farther above the point 2 than it otherwise would be, thereby bringing the thrust-line b b to a greater angle relative to the line a a, and thus increasing the difference between the angles 3 and 3', respectively, and 5 and 5', respectively, besides bringing the latter angles 3 and 5', as hereinbefore pointed out, within the actual angle of repose.

One effect of the organization here set forth, whereby the resistance-center 42 is thrown so far in advance of the resistance center 2, is to throw the center lO of the driving-ring below the line a a, it being at the intersection of the lines a e and d al, respectively, Fig. 5. This variation corresponds with the abovementioned space between the driven wheel and the driving-ring in the plane of the line a a. The important practical advantage resulting from this organization is to bring the lineL of thrust so nearly tangential to the driving-wheel at the center of resistance as to very materially relieve the driving-wheels of the lateral pressure normally due to their engagement with the driving-ring. By this means the driving and driven shafts run under less lateral strain, and correspondingly the friction and heating of the shaft-journals are reduced to a minimum.

For the purpose of further increasing the practical efficiency of the driving-gearing I make in some cases the angle of the frictional faces of the driven wheel less than the angle of the frictional faces of the driving-wheel, these angles being measured, of course, in corresponding planes radial to said wheels, respectively, the angle 5, Fig. 3, being less than the angle 3,Fig. 2, and the corresponding angles of the driving-ring being made to conform to said wheel-groove angles, respectively. The effect of this variation of the angles of the respective wheels is to increase the area of contact between the driven wheel and the inner faces of the driving-ring, and also to increase the adhesion of the drivingring to the driven wheel by reducing the angle 5', Fig. 6. This adhesion tends to carry the driving-ring around with the driven wheel, and thus throw that part of the drivingring in contact with the driving-wheel t0- ward said driving-wheel, thereby constantly tending to forcibly maintain by a species of leverage (the center of resistance et being considered as the fulcrum for said leverage) the contact of the driving-ring with the drivingwheel, notwithstanding the aforesaid slight space at l2, Fig. 3. By means of this feature it is made practicable to so construct and organize the system of gearing as to throw the center of resistance lstill farther in advance of the center of resistance 2, and thus bring the thrust-line l) b still more nearly tangential to the driven Wheel.

It will be understood that in practice the particular angles of the driving-wheel and driven-wheel grooves, respectively, should be worked `out and determined for the particular materials used for the driving-wheels and driving-ring, since the angle of repose, as is well known, varies with the different materials available for the respective purposes.

My present improvements are designed and adapted for use in transmitting a large quantity of power through wheels occupying a relatively small space, it being practicable to transmit by driving-rings, operating as described, a much greater quantity of power than could be transmitted by belts several times the width of the ring. Also, my iniprovements are particularly effective when it is required to drive small wheels from very large wl1eels-as, for instance, for driving dynamos directly from the engine-wheels.

The angle of the wheel-grooves in a radial plane being somewhat greater than the normal angle of repose, the driving-ring as it passes the working zone between the two wheels is easily withdrawn from the wheelgroove, and the angles of the contactingwheel and ring surfaces when measured in the plane of the line of thrust being somewhat less than the normal angle of repose, the thrust of the driving-wheel is transmitted through the driving-ring in the direction of said line of thrust with a tendency to increase the adhesion proportionately to the increase of the driving-power.

Having thus described my invention, I claim-u l. The combination and organization, in frictional gearing, of a driving-wheel and driven wheel grooved substantially as described, the driving-ring freely encircling the driven wheel and engaging the groove-faces of both wheels, the groove-space between the wheels in the plane of their axes being slightly greater than the thickness of the driving-ring, whereby the center of resistance between the driving-ring and driven wheel is brought in advance of the center of resistance of the driving-ring and drivingwheel, the angle of said wheel-grooves measured in planes radial to the wheels being greater than the normal angle of repose and IOO IZO

as described, freely encircling the smaller wheel and engaging the groove-faces of both to Wheels, substantially as described.

FRANK. H. NDERWOOD.

"Witnesses:

GEO. W. LANSING, J. E.v UNDERWOOD. 

